Fluid cooled member for blast



Dec. 27, 1949 R. T. COMER, JR FLUID COOLED MEMBER FOR BLAST FURNACES ANDTHE LIKE Filed Aug. 5, 1948 hummm Ham/ef @Mie/P.,

Patented Dec. 27, 194,9

FLUID COOLED MEMBER FOR BLAST FURNACES AND THE LIKE Robert T. Comer,Jr., Birmingham, Ala., assignor to Tennessee Coal, Iron and RailroadCompany, a corporation of Alabama Application August 5, 1948, Serial No.42,618

(Cl. 26S-38) 4 Claims.

This invention relates to improvements in water-cooled members for blastfurnaces.

Due to the high temperatures generated in the hearth and bosh of blastfurnaces, such as are used for smelting iron ore, and the erosive actionof the molten iron and slag, it is necessary to provide means forcooling brickwork to prolong the life thereof. It has also been foundnecessary to cool the furnace openings through which the blast isintroduced into the hearth, and through which the molten slag is drawnoff between castings in order to withstand the intense physical, thermaland chemical action. Although many other metals have been tried, it isthe general practice to use water-cooled copper or bronze castings forthese purposes. This for the reason in spite of the relatively lowmelting point for copper or bronze, it holds up better than other metalsbecause of its high coefficient conductivity. However, copper or bronzewill not withstand long contact with the molten iron or slag and as aresult, the castings are frequently burned, thus releasing waterv intothe furnace causing delays in blast furnace operations while the burnedcastings are replaced. This replacement of burned water-cooled membersconstitutes a major source of delays in blast furnace operation andlikewise some of the most serious interruptions due to chilled hearthand the like are brought on by failures of these Watercooled parts.

The problem of replacement is particularly acute with respect toso-called cinder notch monkeys, i. e., the opening through which theslag is withdrawn from the furnace. Thus, the average life of bronzemonkeys, in a blast furnace in accordance with a recent check, was 6.54,6.93, and 5.98 days, respectively. The average delay for a burned monkeyduring this period was 28 minutes with a corresponding loss in tonnageand increase in cost.

It is accordingly an object of the present invention to providewater-cooled blast furnace castings having an increased life.

It is another object to reduce delays in blast furnace operation.

It is a further object to provide a blast furnace water-cooled monkeyhaving a materially increased service life.

The foregoing objects will be apparent from the following specificationwhich will particularly describe a blast furnace monkey in conjunctionwith the attached drawing, wherein:

' Figure 1 is a longitudinal section of a blast furnace monkey embodyingthe teachings of my invention; and

Figure 2 is an end view thereof.

Referring more particularly to the drawing, the numeral 2 designates ahollow water-cooled cast blast furnace monkey, preferably formed ofcupreous metal, such'as copper or bronze. The monkey provides a passage4 in the brickwork wall l6 of the blast furnace (not shown) for theremoval of the molten slag from the furnace. Cooling water is admittedto the monkey 2 through a suitable opening 8 and withdrawn through asimilar'opening I 0. A baiiie I2 may be provided intermediate theopenings 8 and I0 to provide positive circulation of the cooling waterthrough the internal cavity I4 in the cooling member.

Such -members have the dual function of cooling the brickworksurrounding them and protecting the brickwork from the corrosive actionof molten slag withdrawn therethrough. In order to better accomplishthis latter function and, in accordance with the teachings of myinvention, the inner exposed end portion I6 and the inside I8 throughwhich the molten material passesare plated with a metal coating 20, thecoating metal having a melting point in excess of the hearthtemperatures in the furnace. With low silicon basic iron, the hearthtemperatures will not exceed 2600 F. whereby a coating material having amelting point in excess of 2600 F. such as nickel which has a meltingtemperature of. 2646 F. is quite satisfactory. However,

the cupreous water-cooled member without low-` ering the cooling effectthereof, should have a thickness of the order called for by thefollowing v formula:

wherein L1=thickness of chromium K1=thermal conductivity of coatingmetal AT1=temperature drop in coating metal L2=thickness of castingmetal Kz-:thermal conductivity of casting metal AT2=temperature drop incasting metal While a coating having a slightly greater thickness may beused, it is essential that coating have a thickness at least as great asthat indicated by the foregoing formula.

Actual blast furnace operations have shown that cupreous monkeys coatedwith chromium of the foregoing thickness, have a service life in ex- 60cess of 30 days as compared to the 5 to 6-day 3 average above noted.Similarly other watercooled members used in blast furnaces, such astuyres, tuyre coolers, bosh cooling plates, shell cooling plates, cindercoolers and the like, may have their life correspondingly increasedwithout lowering the cooling eiliciency thereof.

While I have shown and described one specic embodiment of my invention,it will be understood that this embodiment is merely for the purpose ofillustration and description and that various other forms may be devisedwithin the scope of my invention, as deiined in the appended claims.

I claim:

1. A water-cooled member for blast furnaces comprising a hollow castingformed of cupreous metal, said casting having an external layer of metalhaving a melting point above 2600" F., said external layer having aminimum thickness determined by the formula galt K, AT, L

- wherein L1=thickness of the external coating K1=therma1 conductivityof coating metal AT1=temperature drop in coating metal L2=wall thicknessof casting metal K2=thermal conductivity of casting metalAT2=temperature drop in casting metal.

2. A water-cooled member for blast furnaces comprising a hollow castingformed of cupreous metal, said casting having an external layer of metalhaving a melting point above 2750 F., said external layer having aminimum thickness determined by the formula 2l 3. A water-cooled monkeyfor blast furnaces comprising a hollow casting formed oi cupreous metal,said casting having an external layer of chromium, said chromium layerhaving a minimum thickness determined by the formula whereinL1=thicknessof the external coating K1=thermal conductivity of coatingmetal AT1=temperature drop in coating metal L2=wall thickness of castingmetal K2=thermal conductivity of casting metal AT2=temperature drop incasting metal.

4. A water-cooled monkey for blast furnaces comprising a hollow castingformed of cupreous metal, said casting having an external layer otchromium, said chromium layer having a thickness determined by theformula wherein L1=thickness of the external coating K1=therma1conductivity of coating metal AT1=temperature drop in coating metalLz=wal1 thickness of casting metal K2=thermal conductivity of castingmetal AT2=temperature drop in casting metal ROBERT T. COMER, Jn.REFERENCES CITED The following references are of record in the

